Who Eats Who?… And Where Do They Eat? | By Chris Fuller

Lakes are complicated.  There is no single answer to any given question when it comes to lake ecology.  Two lakes may have different dynamics based solely on their bottom shape and depth, even though they may have the same species present, the same nutrient inputs, and the same climate.  Here in Bella Vista, we have relatively deep and steep-sided lakes, and this plays a part in the food web dynamics of fish.

Fish can be picky when it comes to where they hang out.  This is usually based on a combination of hiding spots and food availability.  Largemouth bass for example, like shoreline habitat with open rocky bottoms, peppered with structure and vegetation, where they can stalk and ambush prey.  Juvenile bluegill and other panfish prefer thick vegetation with patches of fine gravel in shallow water where they can look for bugs and have plenty of hiding spaces.  Gizzard shad and silversides like deep open water where they can school and filter feed on plankton, however, gizzard shad may move to coves at dawn and dusk to feed on detritus.  Hybrid striped bass prefer the open water where they can school and chase shad and silversides.

It is not obvious, but the shape of the lake has a big impact on the interactions of fish based on where they like to hang out.  In many southern impoundments, the average depth is relatively shallow, and there really isn’t deep open water.  This leads to a great deal of overlap in habitat, where shoreline fish like largemouth bass and bluegill more often encounter open-water fish, like shad, silversides, and hybrid striped bass.  This has led to a lot of misunderstandings about fish dynamics.  Many anglers and managers assume that stocking shad means another food source for largemouth bass.  This may or may not be true based on the physical dimensions of the lakebed and water depth.  In shallow lakes, with high nutrient inputs, like those found in lowland areas, shad have proven an important food source for largemouth bass.  In lakes with deep open water, habitat preferences mostly keep these two species separated, and there is little interaction between them.  Diet studies conducted on Bella Vista lakes, as well as diet studies on other lakes, show this to be true.  Largemouth bass feed primarily on bluegill and crayfish, while only consuming shad in any capacity during the fall.  Meanwhile, hybrid striped bass and striped bass feed primarily on shad and consume very few bluegill or crayfish.  Understanding fish dynamics based on habitat is an important step in determining management strategies and could also help bridge the gap between angler desires and lake manager actions.